Coded light detector

ABSTRACT

A coded lighting system comprises a set of light sources and a remote control unit or an arrangement. The set of light sources emits coded light. In order to do so each light source is associated with a unique identifier. The remote control unit or the arrangement comprises an image sensor which captures images comprising light emitted by at least one of the light sources in the set of light sources. By analyzing the captured images the remote control unit or the arrangement is able to associate light sources affecting a particular region and/or object. The remote control unit or the arrangement is thereby able to transmit a control signal comprising updated light settings to the set of light sources.

CROSS REFERENCE TO PRIOR APPLICATIONS

This application is a Continuation application of U.S. application Ser.No. 14/351,153, filed on Apr. 11, 2014, which is the U.S. National PhaseApplication of International Application No. PCT/IB2012/055174, filed onSep. 28, 2012 and claims the benefit of U.S. Provisional Application No.61/547,101, filed on Oct. 14, 2011. These applications are herebyincorporated by reference herein.

FIELD OF THE INVENTION

The present invention relates to the field of coded light and inparticular to a remote control unit and a method for controlling a setof light sources emitting coded light.

BACKGROUND OF THE INVENTION

The advent of integrated lighting installations, consisting of an evergrowing number of individually controllable light sources, luminaires,lighting arrangements and the like with advanced rendering capabilities,may be regarded as transforming lighting systems for both professionaland consumer markets. This brings a need for an intuitive controlcapable of fully exploiting the rendering capabilities of the completelighting infrastructure. Several approaches have been proposed tocontrol light sources, luminaires, lighting arrangements and the like.

A first example involves wall-mounted control. At commissioning time aset of wall-mounted controls are installed, each of them controlling anindividual or group of light sources or luminaires, possibly withoptimized controls for each type of control within the set.

A second example involves having a separate remote control unit for eachindividual light source or luminaire. This may be regarded, by means ofthe remote control unit, as a more or less straight forward extension ofthe above disclosed wall switch control.

A third example involves iterative selection of the individual lightsources or luminaires. A user is provided with a simple remote controlunit capable of controlling all light sources or luminaires which theremote control unit has been commissioned with. The remote control unitis able to control a single luminaire at a time, but it may also allow auser to browse through all the luminaires, for example by manipulationof a user interface provided on the remote control unit (e.g. by using“previous” or “next” buttons). A digital version of such a concept hasalso been developed, which adopts a touch screen device as a remotecontrol unit, so that, once a light source or luminaire is selected, alight control optimized for such a light source or luminaire isdisplayed to the user (e.g. color temperature for a light source orluminaire with tunable white; or a color wheel for an RGB light) bymeans of the touch screen on the remote control unit.

A fourth example involves the concept of point and control; thisapproach exploits the principle of coded light and a remote control unitcapable of detecting the code of the light source or luminaire towardwhich the remote control unit is pointed and thereby to identify thelight source or luminaire emitting the coded light. Such a remotecontrol unit typically comprises one or more photodiodes for detectingthe coded light emitted by the light source or luminaire. In general,coded light has been proposed to enable advanced control of lightsources. Coded light is based on embedding of data, inter alia invisibleidentifiers, in the light output of the light sources. Coded light maythus be defined as the embedding of data and identifiers in the lightoutput of a visible light source, f.i. applying CDMA modulationtechniques, wherein the embedded data and/or identifier preferably donot influence the primary lighting function of the light source. Hence,any modulation of the emitted light pertaining to data and/or identifiershould be invisible to humans. This allows for applications such asinteractive scene setting, commissioning and re-commissioning ofnetworked lighting systems. Coded light may be used in communicationsapplications wherein one or more light sources in a coded lightingsystem are configured to emit coded light and thereby communicateinformation to a receiver.

The point and control approach shows the advantage of using coded lightas a means to be able to select a luminaire by simply pointing towardsit. As noted above, this approach employs a photodiode in order todetect the Coded Light message of each luminaire. It has been proposedto detect and decode coded light by means of a standard camera.

International application WO 2009/010926 relates to a method forprocessing light in a structure where the light sources emit lightcarrying individual codes. A camera is arranged in a camera position ofthe structure and registers images of spots of the light. WO 2009/010926is based on an insight that by using a camera for registering images ofthe light emitted from the light sources after installation thereof, andrecognizing the individual codes in the registered images, it ispossible to obtain a fast and at least substantially automaticdetermination of light source properties. The camera may comprise animage detector comprising a matrix of detector elements each generatingone pixel of the registered image. The camera registers images ofilluminated areas at a frequency that corresponds to, or is adapted to,the modulation frequency of CDMA modulation. Thereby it is possible forthe camera to generate images that capture different CDMA codes of thedifferent illuminated areas.

SUMMARY OF THE INVENTION

The inventors of the enclosed embodiments have identified a number ofdisadvantages with the above noted first, second, third and fourthexamples. For example, it may be time consuming because the user needsto either browse through all light sources or luminaires (as in thethird example), or point the remote control unit toward each individuallight source or luminaire (as in the fourth example).

For example, the above disclosed arrangements of light sources orluminaires and remote control units are not scalable. With an increasingnumber of light sources and luminaires in the arrangement, browsingthrough each light (as in the third example), or carrying along anindividual remote control unit for each light (as in the second example)can be a tedious and error prone process.

For example, the above disclosed arrangements of light sources orluminaires and remote control units are not flexible. A wall mountswitch for every configuration would have to be modified or added once anew type of setting, or subset of light sources or luminaires would needto be defined (as in the first example).

It is an object of the present invention to overcome these problem, andto provide a remote control unit and a method for controlling a set oflight sources emitting coded light that are less time consuming,scalable, and flexible without being complex or error prone.

According to a first aspect of the invention, this and other objects areachieved by a remote control unit for controlling a set of lightsources, comprising an image sensor arranged to capture at least oneimage and to detect coded light in the at least one image; a processingunit arranged to determine a region and/or object in an image capturedby the image sensor; associate, by virtue of the detected coded light,the determined region and/or object with a set of light sources emittingthe detected coded light, each light source having one or more lightsettings, wherein the region and/or object in the image is illuminatedat least by the set of light sources; receive an input signal relatingto updated light settings of the set of light sources; and a transmitterarranged to transmit a control signal corresponding to the updated lightsettings to the set of light sources.

Such a remote control unit may advantageously shorten the time needed todetermine settings for a set of light sources in a coded lighting systemsince it does not require a remote control to receive coded lightexclusively from one of the light sources one by one. The disclosedremote control unit advantageously also scales with the number of lightsources in the system since the functionality of the disclosed remotecontrol unit is independent of the number of light sources in thesystem. Furthermore, the disclosed approach allows a user to focus onthe desired light effects, regardless of the number and location oflight sources. An example of this would imply a user interface whichpresents to the user settings for the overall light effect affecting theselected area/object, instead of a specific user interface for eachindividual light source influencing the area/object. This type ofinterface may be preferred for quick settings, while an interfaceallowing to individually set the parameters of each light sourceaffecting the area would be preferred when accuracy and full control ofthe light settings is necessary.

The processing unit may be further arranged to receive at least twoimages from the image sensor and to detect a difference between the atleast two images; and determine the region and/or object in one of thetwo images from the difference. The remote control unit may thusadvantageously identify the object and/or region from captured images.

The processing unit may be further arranged to receive user inputidentifying an area in the image; and from the identified area determinean outline of the object and/or region so as to determine the objectand/or region. The remote control unit may thus advantageously identifythe object and/or region from user input.

The remote control unit may further comprise a user interface arrangedto provide the processing unit with the user input upon user interactionwith the user interface. The user interface may advantageously comprisea touch sensitive display which thus provides for easy identification ofthe region and/or object by the user of the remote control unit.

The image sensor may further be arranged to capture a plurality ofimages so as to form a stack of images from the plurality of images;determine the sum over all pixels per image in the stack of images togenerate a conventional one-dimensional signal to determine which codesare present in a scene represented by the stack of images; anddetermine, from the stack of images, a footprint of the light source bycorrelating time dependence of all pixels with a code associated withthe light source.

This may be possible either by using synchronization of the light sensorwith the set of light sources, or by exploiting the rolling shuttercharacteristics of the image sensor. A light sensor embodied as astandard camera with a beam splitter and a photodiode may be able tomaintain an overview of the environment, by means of the camera, and atthe same time be able to detect codes at extremely high accuracy andspeed, by means of the photodiode.

The processing unit may further be arranged to transmit identificationof the region and/or object to the user interface. This mayadvantageously provide the user with feedback regarding the identifiedregion and/or object.

The user interface may be arranged to provide a snapshot of the imagecomprising the object and/or region together with and indication of theobject and/or region. This may advantageously further improve thefeedback provided to the user.

The user interface may be arranged to provide an indication relating towhich light source or light sources that affect illumination of theobject and/or region. This may advantageously provide the user withfeedback regarding the light sources.

The user interface may be arranged to provide light settings availablefor the set of light sources. This may advantageously provide the userof the remote control unit the possibility to change one or more lightsettings of the light source(s) affecting the identified region and/orobject.

The processing unit may be further arranged to identify the regionand/or object by segmenting image foreground information from imagebackground information and to identify the region and/or object byvirtue of the image foreground information. This may advantageouslyenable improved identification of the region and/or object.

The processing unit may be further arranged to identify the regionand/or object by performing motion detection and/or estimation betweenthe two images in order to detect an object and/or region that has movedbetween the two images. This may advantageously enable improvedidentification of the region and/or object.

The processing unit may be further arranged to identify the regionand/or object by performing depth segmentation so as to obtain an imagedepth measurement from which the region and/or object is identified.This may advantageously enable improved identification of the regionand/or object.

The processing unit may be further arranged to identify the regionand/or object by performing object detection. This may advantageouslyenable improved identification of the region and/or object.

According to a second aspect of the invention, the objective is achievedby an arrangement comprising a remote control unit according to theabove and at least one luminaire controllable by the remote control unitand comprising at least one light source from the set of light sources.

According to a third aspect of the invention, the objective is achievedby method for controlling a set of light sources, comprising capturing,by an image sensor, at least one image and detecting coded light in theat least one image; determining, by a processing unit, a region and/orobject in an image captured by the image sensor; associating, by theprocessing unit, by virtue of the detected coded light, the determinedregion and/or object with a set of light sources emitting the detectedcoded light, each light source having one or more light settings,wherein the region and/or object in the image is illuminated at least bythe set of light sources; receiving, by the processing unit, an inputsignal relating to updated light settings of the set of light sources;and transmitting, by a transmitter, a control signal corresponding tothe updated light settings to the set of light sources.

It is noted that the invention relates to all possible combinations offeatures recited in the claims. Likewise, the advantages of the firstaspect apply to the second aspect as well as the third aspect, and viceversa.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other aspects of the present invention will now bedescribed in more detail, with reference to the appended drawingsshowing embodiment(s) of the invention.

FIGS. 1a and 1b illustrate lighting systems according to embodiments;

FIG. 2 illustrates a remote control unit;

FIGS. 3a, 3b, 3c and 4 illustrate images as captured by an image sensor;

FIG. 5 illustrates an example of a user interface of a remote controlunit or an arrangement; and

FIGS. 6a and 6b are flowcharts according to embodiments.

DETAILED DESCRIPTION

The below embodiments are provided by way of example so that thisdisclosure will be thorough and complete, and will fully convey thescope of the invention to those skilled in the art. Like numbers referto like elements throughout.

Recent development, such as exemplified by International application WO2009/010926, has shown the possibility to detect coded light with theuse of standard cameras Hereinafter a system which exploits a similarprinciple, combined with computer vision algorithms to automaticallydetect which luminaires are mostly influencing an object which isinserted, or recently moved, in the scene will be described.

Operation of a lighting system will now be disclosed with reference tothe lighting systems 1 a of FIGS. 1a and 1b of FIG. 1b , and theflowcharts of FIGS. 6a and 6b . The lighting systems 1 a and 1 b ofFIGS. 1a and 1b comprise at least one light source arranged to emitcoded light, schematically denoted by light sources with referencenumerals 2 a, 2 b, 2 c. The at least one light source 2 a-c may be aluminaire and/or be part of a lighting control system. The lightingsystems 1 a and 1 b may thus be denoted as coded lighting systems. Aluminaire may comprise at least one light source 2 a-c. The term “lightsource” means a device that is used for providing light in a room, forpurpose of illuminating objects in the room. A room is in this contexttypically an apartment room or an office room, a gym hall, an indoorretail, environment, a theatre scene, a room in a public place or a partof an outdoor environment, such as a part of a street. Each light source2 a-c is capable of emitting coded light, as schematically illustratedby arrows 3 a, 3 b, 3 c. The emitted light thus comprises a modulatedpart associated with coded light comprising information sequences. Theemitted light may also comprise an un-modulated part associated with anillumination contribution. Each light source 2 a-c may be associatedwith a number of light (or lighting) settings, inter alia pertaining tothe illumination contribution of the light source, such as color, colortemperature, intensity and frequency of the emitted light. In generalterms the illumination contribution of the light source may be definedas a time-averaged output of the light emitted by the light source 2a-c.

The system 1 a further comprises a device termed a remote control unit 4arranged to receive and detect the coded light emitted by the lightsources in the system 1 a. The remote control unit 4 therefore comprisesan image sensor 5 for detecting the light emitted by the light source(s)in the system 1 a by capturing images comprising coded light. The remotecontrol unit 4 further comprises a processing unit 6 operatively coupledto the image sensor 5. The processing unit 6 analyzes images captured bythe image sensor 5 and identifies changes in the scene defined by thecaptured images, and particularly objects which have been moved orinserted in the scene. The remote control unit 4 further comprises atransmitter 7 operatively coupled to the processing unit. Thetransmitter 7 is arranged to transmit data, as schematically illustratedby arrows 8 a, 8 b to one or more of the light sources in the system 1a. The remote control unit 4 may further comprise other components, suchas a memory 9 operatively coupled to the processing unit 6 and a userinterface 16 also operatively coupled to the processing unit 6. Theremote control unit 4 may be part of a mobile phone and the hereindisclosed functionality may be provided as one or more applications,so-called “Apps”. The one or more applications may be stored as one ormore software products stored on a computer-readable storage medium.

In the alternative embodiment of FIG. 1b , the system 1 b comprises anarrangement 20. The arrangement 20 comprises a number of physicallyseparated (but operatively connectable) devices which when operationallyconnected (or coupled) enable the arrangement 20 arranged to receive anddetect the coded light emitted by the light sources in the system 1 b.The arrangement 20 therefore comprises an image sensor 5 for detectingthe light emitted by the light source(s) in the system 1 b by capturingimages comprising coded light. The arrangement 20 further comprises aprocessing unit 6 operatively coupled to the image sensor 5. Theprocessing unit 6 analyzes images captured by the image sensor 5 andidentifies changes in the scene defined by the captured images, andparticularly objects which have been moved or inserted in the scene. Thearrangement 20 further comprises a transmitter 7 operatively coupled tothe processing unit 6. The transmitter 7 is arranged to transmit data,as schematically illustrated by arrows 8 a, 8 b to one or more of thelight sources in the system 1 b. The arrangement 20 may further compriseother components, such as a memory 9 operatively coupled to theprocessing unit 6 and a user interface 16 also operatively coupled tothe processing unit 6. The arrangement 20 may be advantageous inscenarios in which the image sensor 5 is either mounted fixed at theceiling of the space to be illuminated by the light source 2 a-c, orpositioned at a certain location while an operator of the lightingsystem 1 b is free to move around and change light settings while beingin the scene himself/herself. The change of lighting settings will befurther explained below. As an example, arranging the image sensor 5fixed at the location enables the operator to move around freely in thearea to be illuminated whilst interacting with the user interface 16(which thus may be provided in a device which is physically differentfrom the device holding the image sensor 5), whereby images of the sceneto be illuminated could be wirelessly transmitted from the deviceholding the image sensor 5 to the device holding the user interface 16.This may also relieve the operator from having to point at the scene tobe illuminated while changing the light settings. The processing unit 6may be provided either in the device holding the image sensor 5, in thedevice holding the user interface 16, or in a third device.

Thus, whereas the remote control unit 4 of FIG. 1a represents anembodiment according to which the particularly the image sensor 5, theprocessing unit 6, and the transmitter 7 are part of one and the samephysical device (i.e. the remote control unit 4), the arrangement 20 ofFIG. 1b represents an embodiment according to which the image sensor 5,the processing unit 6, and the transmitter 7 are not necessarily part ofone and the same device, but instead provided as two or more physicallyseparated, but operatively coupled, devices.

FIG. 2 schematically illustrates, in terms of a number of functionalblocks, the remote control unit 4, the components of which may also bepart of the arrangement 20. The remote control unit 4 (and hence alsothe arrangement 20) comprises an image sensor 5 for receiving codedlight from at least one light source, such as the light sources 2 a-c inthe lighting systems 1 a, 1 b. In a step S2 the image sensor 5 capturesat least one image. The image sensor 5 then detects coded light in theat least one image. How coded light is detected in the at least oneimage will be further disclosed below. The image sensor 5 is furtherarranged to capture images within a field of view 10 a-10 b along ageneral light detection direction. The image sensor 5 is thus able toreceive and detect light, particularly coded light, within the field ofview 10-10 b. The general light detection direction can be changed bychanging the direction of the image sensor 5. The field of view 10 a-10b may be narrowed by the remote control unit 4 performing a zoom-inoperation. Similarly, the field of view 10 a-10 b may be broadened bythe remote control unit 4 performing a zoom-out operation. Thereby theimage sensor 5 is enabled to capture images in a plurality of differentdirections and with a plurality of different fields of view. The remotecontrol unit 4 (and hence also the arrangement 20) may thereby bearranged to identify an individual lighting device 2 a-2 c from thegroup of said at least one light source 2 a-2 c. For example the imagesensor 5 may be able to detect the physical direction from which thedetected light is emanating. These physical directions are in FIGS. 1aand 1b schematically denoted by arrows 3 a-3 c, which indicate the lightemanating from the light source 2 a-2 c. As a second example theindividual light source 2 a-2 c may be identified by said lightingdevice identification codes, which, as discussed above, may be embeddedin the emitted light contributions of the light source 2 a-2 c.

Since each individual light source 2 a-2 c is associated with a uniquelighting device identification code each individual light source 2 a-2 cmay be identified. In order to do so the image sensor 5 may in a stepS12 first capture a plurality of images so as to form a stack of imagesfrom the plurality of images (down sample if no higher resolution isneeded). The image sensor 5 may in a step S14 determine the sum over allpixels per image in the stack of images to generate a conventionalone-dimensional signal (in time) to determine which codes (and withwhich phase/time delay) that are present in the scene represented by thestack of images. The image sensor 5 may then in a step S16 use the stackof images to determine footprints of every light source 2 a-2 c bycorrelating the time dependence of all pixels with the correspondingcode (and phase, from the previous step).

The remote control unit 4 (and hence also the arrangement 20) furthercomprises a processing unit 6. The processing unit 6 may be implementedby a so-called central processing unit (CPU). In the typical scenariosof FIGS. 1a and 1b , the image sensor 5 of the remote control unit 4 (orthe arrangement 20) detects the light emitted by the one or more lightsources 2 a-2 c (the light being within the field of view 10 a-10 b ofthe image sensor 5). The light comprises coded light defining a uniquelighting device identification code. For example such an identificationcode may be realized as a pulse width modulation code. As a secondexample the identification code may be realized by using code divisionmultiple access techniques. It is to be understood that otherembodiments for the realization of identification codes are known to aperson skilled in the art.

As will be further elaborated upon below the remote control unit 4 (andhence also the arrangement 20) may further comprise a user interface 16through which a user is enabled to interact with the functionality ofthe remote control unit. Thus the user interface 16 may in particular bearranged to receive user input and to provide information to the user.

FIGS. 3a, 3b, 3c and 4 illustrate possible embodiments of controlling aset of light sources emitting coded light using the disclosed remotecontrol unit 4 (or the arrangement 20). FIGS. 3a, 3b, 3c and 4 commonlydepict an environment with several coded light sources 2 a, 2 b, 2 c, 2d as captured by an image sensor 5 of the remote control 4 (or thearrangement 20). Once a new object 13 is placed in the scene, the imagesensor 5 is used to detect the presence and location of the object 13.The region and/or object in the image is thus illuminated at least bythe set of light sources 2 a-b emitting the coded light. The regionand/or object in the image may also be illuminated by additional lightsources. Exploiting the principles described above for identifyingindividual light sources, the image sensor 5 is able to detect (andthereafter select) the coded light sources which are mostly affectingthe new object. In the example of FIGS. 3a, 3b, 3c and 4 the lightsources affecting the object 13 are those with reference numerals 2 aand 2 b. Each one of the FIGS. 3a, 3b, 3c and 4 will now be described inmore detail.

FIG. 3a illustrates a first image 11 a as captured by the image sensor 5of the remote control unit 4 (or the arrangement 20). The image 11 a maybe presented to a user interface of the remote control unit 4 (or thearrangement 20). The image 11 a depicts a scene comprising light sources2 a-2 c emitting coded light 12 a-12 d.

FIG. 3b illustrates a second image 11 b as captured by the image sensor5 of the remote control unit 4 (or the arrangement 20). In comparison tothe first image 11 a of FIG. 3a the second image 11 b depicts the samescene as the image 11 a with the difference that an object 13 has beenadded to the image 11 b. The added object 13 may be detected by theprocessing unit 6. Particularly the processing unit 6 is arranged to, ina step S4, determine a region and/or object in an image captured by theimage sensor 5. The processing unit 6 may utilize one of a number ofways to detect the added object 13.

According to an embodiment the processing unit 6 is further arranged toin a step S18 receive at least two images, such as the first image 11 aand the second image 11 b, from the image sensor 5 and to detect adifference between the at least two images 11 a, 11 b. In the exemplaryscenario of the first image 11 a and the second image 11 b of FIGS. 3aand 3b respectively the difference is defined by the object 13 havingbeen added in image 11 b. The object 13 may thus be determined by theprocessing unit 6, in a step S20, in one of the two images 11 a, 11 bfrom the difference there between.

Background segmentation may be used alternatively or in combinationtherewith to determine the region and/or object 13 in one or more imagescaptured by the image sensor 5. In background segmentation foregroundsegmentation mask is computed so as to separate the region and/or objectfrom the background. Particularly, the processing unit 6 may further bearranged to in a step S22 identify the region and/or object 13 bysegmenting image foreground information from image backgroundinformation and to identify the region and/or object 13 by virtue of theimage foreground information.

Motion detection/estimation may, in a step S24, be used alternatively orin combination therewith by the processing unit 6 to determine theregion and/or object 13 in one or more images captured by the imagesensor 5. In motion detection/estimation a map of all areas of the imagewhich moved in the recent past is computed. The processing unit 6 maythus in particular be arranged to detect an object and/or region thathas moved between the two images.

Depth segmentation may, in a step S26, be used alternatively or incombination therewith by the processing unit 6 to determine the regionand/or object 13 in one or more images captured by the image sensor 5.In depth segmentation a map of what changed in the environment isobtained. Recent advances in 3D optical ranging have proven how toobtain a depth measurement for each pixel of a regular camera. Theprocessing unit 6 may thus in particular be arranged to detect an objectand/or region from an image depth measurement from which the regionand/or object is identified.

Object detection may, in a step S28, be used alternatively or incombination therewith by the processing unit 6 to determine the regionand/or object 13 in one or more images captured by the image sensor 5.In object detector the processing unit 6 could be trained to recognizeonly a specific category of objects, such as people, shoes, vegetables,etc., so that only if an object belonging to one of those categoriesappears in the scene a region would be made available.

The added object 13 may alternatively be detected from user interaction.In order to do so the remote control unit 4 (and hence also thearrangement 20) may comprise a user interface 16. The user interface 16advantageously comprises a touch sensitive display. Touch sensitivedisplays and their functions are as such known in the art. The touchsensitive display may in particular be arranged to provide theprocessing unit 6 with the user input upon user interaction with thetouch sensitive display. The user interface may also be gaze based orbased on tactile interaction. If the user interface 16 is gaze based theremote control unit 4 (or the arrangement 20) advantageously comprises acamera unit arranged to be directed towards one eye (or both eyes) ofthe user of the control unit 4 (or the user interface 16 of thearrangement 20) and where the processing unit 6 uses eye-tracking so asto determine the point of gaze of the user to determine an object and/orregion in the displayed image. The user input may receive tactile userinput for example from a keyboard or a joystick provided on, or beingoperatively coupled to, the remote control unit 4 (or the arrangement20). As the skilled person understands, there may be other equallylikely and equivalent ways of receiving user input.

FIG. 3c illustrates a third image 11 c as captured by the image sensor 5of the remote control unit 4 (or the arrangement 20). In comparison tothe second image 11 b of FIG. 3b the second image 11 c depicts the samescene as the image 11 b with the difference that a marker 14 marking theobject 13 has also been added to the image 11 c. For example, a user ofremote control unit 4 (or the arrangement 20) may be allowed to point toan object in one of the images captured by the image sensor 5. Theprocessing unit may therefore further be arranged to, in a step S30,receive user input identifying an area in the image. The received userinput may be acknowledged to the user by providing the marker 14. Thecomplete object outline may then be automatically segmented exploitingcomputer vision techniques as disclosed above. Thus from the identifiedarea an outline of the object and/or region may be determined by theprocessing unit in a step S32 so as to determine the object and/orregion. From the selected image area, all the relevant codes, i.e. codesassociated with light sources 2 a, 2 b at least partly illuminating theidentified area and/or object 13, can then be selected.

Once one or several relevant regions/objects have been detected, theuser may, in a step S34, receive a snapshot of the image captured by theimage sensor 5. Optionally the snapshot may be provided together with anindication, in a step S36, of which regions/objects that have beenselected. The snapshot may be provided by the user interface 16. FIG. 4illustrates such a snapshot image 11 c as captured by the image sensor 5of the remote control unit 4 (or the arrangement 20). The image 11 cdepicts the same scene as the images 11 b and 11 c. In addition theimage 11 c comprises and indication, in the form of a dotted line 15, ofthe detected object 13. Information pertaining to the indication is thusoriginally generated by the processing unit 6 in response to detectingthe object 13 and may then be transmitted, in a step S38, from theprocessing unit 6 to the user interface 16 so as to provide theindication to the user. Alternatively, no image/indication is providedto the user. Instead, once a region/object has been detected, the lightsources 2 a, 2 b affecting the region/object may provide visibleindication, such as emitting one or more blinkings, so that the user canrecognize which region/object that is currently selected. In such a casethe remote control unit 4 (or the arrangement 20) upon detection of theregion/object and identification of the light sources 2 a, 2 b affectingthe region/object transmits a control signal to the light sources 2 a, 2b to provide the visible indication.

By virtue of the detected coded light the processing unit 6 is furtherarranged to, in a step S6, associate the determined region and/or objectwith a set of light sources 2 a-b emitting the coded light, where thecoded light has been detected by the image sensor 5 in step S2. Once aregion/object is detected, the user may additionally be presented with auser interface through which the user is enabled to change one or moreapplicable lighting settings or properties of the light sources 2 a, 2 baffecting the detected region/object, step S40. This is illustrated inFIG. 5. Particularly, the processing unit 6 is in a step S8 arranged toreceive an input signal relating to updated light settings of the set oflight sources 2 a, 2 b.

FIG. 5 shows an example of a user interface 16 of the remote controlunit 4. With respect to the arrangement 20 the user interface 16 may beprovided as a separate physical unit. Controllable properties of thelight may pertain to color of the emitted light, the color temperatureof the emitted light, the intensity of the emitted light and/or theblinking frequency of the emitted light. In the example of FIG. 5 thisis illustrated by a number of available settings 18 with which a usermay interact by setting values of respective slidebars 19. The userinterface thereby enables controlling lights by the setting of theproperties of the particular group of light affecting the detectedregion/object.

As noted above the remote control unit 4 (and hence also the arrangement20) further comprises a transmitter 7. The transmitter 7 is arranged to,in a step S10 transmitting a control signal corresponding to the updatedlight settings to the set of light sources 2 a, 2 b. The set of lightsources 2 a, 2 b is thereby controlled by the remote control unit 4.

The remote control unit 4 (and hence also the arrangement 20) mayfurther comprise other components, such as a memory 9 operativelycoupled to the processing unit 6. The memory 9 is operated according toprinciples which as such are known by the skilled person. Particularly,the memory 9 may comprise a set of lighting settings which may betransmitted to light sources 2 a-2 c in the lighting systems 1 a, 1 b.The transmitter 7 may be a light transmitter configured to emit codedlight. Alternatively the transmitter 7 may be a radio transmitterconfigured to wirelessly transmit information. The transmitter 7 may beconfigured for bidirectional communications. The transmitter 7 maycomprise a radio antenna. Alternatively the transmitter 7 may comprise aconnector for wired communications.

The person skilled in the art realizes that the present invention by nomeans is limited to the preferred embodiments described above. On thecontrary, many modifications and variations are possible within thescope of the appended claims. Particularly, the disclosed remote controlunit 4 and at least one luminaire comprising at least one light source 2a, 2 b, 2 c and being controllable by the remote control unit 4 may beprovided as an arrangement.

In summary, the disclosed embodiments are applicable to severalscenarios: in retail lighting, it allows shopping personnel to easilyselect luminaires affecting a new product inserted in a shopping window;for a light designer, it allows to move in the environment to a certainlocation, and automatically be able to choose lights which affect suchposition, without any need of a pointing device.

The invention claimed is:
 1. A remote control unit for controlling a set of light sources, comprising an image sensor arranged to capture at least one image and to detect coded light in said at least one image; a processing unit arranged to: receive at least two images from the image sensor, and detect a difference between the at least two images; determine a region and/or object in an image captured by the image sensor; use said detected coded light to identify a set of light sources emitting said detected coded light that are illuminating said region and/or object, each light source having one or more light settings; and receive an input signal relating to updated light settings of said set of light sources; and a transmitter arranged to transmit a control signal corresponding to said updated light settings to said set of light sources.
 2. The remote control unit according to claim 1, wherein the processing unit is further configured to; determine the region and/or object in one of the two images from said difference.
 3. The remote controller according to claim 1, wherein the processing unit is further configured to: receive user input identifying an area in the image; and from the identified area determine an outline of the object and/or region so as to determine the object and/or region.
 4. The remote control unit according to claim 3, further comprising a user interface (16) arranged to provide the processing unit with the user input upon user interaction with the user interface.
 5. The remote control unit according to claim 1, wherein the image sensor is further configured to: capture a plurality of images so as to form a stack of images from said plurality of images; determine the sum over all pixels per image in said stack of images to generate a conventional one-dimensional signal to determine which codes that are present in a scene represented by the stack of images; and determine, from the stack of images, a footprint of the light source by correlating time dependence of all pixels with a code associated with the light source.
 6. The remote control unit according to claim 1, further comprising a user interface, and wherein the processing unit is further configured to transmit identification of said region and/or object to the user interface.
 7. The remote control unit according to claim 6, wherein the user interface is arranged to provide a snapshot of the image comprising the object and/or region together with and indication of the object and/or region.
 8. The remote control unit according to claim 6, wherein the user interface is arranged to provide an indication relating to which light source or light sources that affect illumination of the object and/or region.
 9. The remote control unit according to claim 8, wherein the user interface is arranged to provide light settings available for said set of light sources.
 10. The remote control unit according to claim 1, wherein the processing unit is further arranged to identify the region and/or object by segmenting image foreground information from image background information and to identify the region and/or object by virtue of the image foreground information.
 11. The remote control unit according to claim 2, wherein the processing unit is further arranged to identify the region and/or object by performing motion detection and/or estimation between the two images in order to detect an object and/or region that has moved between the two images.
 12. The remote control unit according to claim 1, wherein the processing unit is further arranged to identify the region and/or object by performing depth segmentation so as to obtain an image depth measurement from which the region and/or object is identified.
 13. The remote control unit according to claim 1, wherein the processing unit is further arranged to identify the region and/or object by performing object detection.
 14. An arrangement comprising a remote control unit according to claim 1 and at least one luminaire controllable by the remote control unit and comprising at least one light source from said set of light sources.
 15. A method for controlling a set of light sources, comprising: capturing, by an image sensor, at least two images and detecting coded light in at least one of said images and a difference between the at least two images; determining, by a processing unit, a region and/or object in an image captured by the image sensor; the processing unit, identifying, using said detected coded light, a set of light sources emitting said detected coded light that are illuminating the determined region and/or object, each light source having one or more light settings; receiving, by the processing unit, an input signal relating to updated light settings of said set of light sources, wherein the input signal sets an overall light effect affecting the determined region and/or object; and transmitting, by a transmitter, a control signal corresponding to said updated light settings to said set of light sources.
 16. The method of claim 15, wherein the region and/or object is determined in one of the two images from said difference. 